In recent years, with the tendency for increased integration and miniaturization of electronic devices, studies on nanostructured materials and fabrication methods thereof have been very actively conducted.
Particularly, it is thought that techniques for fabricating large-area nanopatterns of high resolution and high aspect ratio are necessary to achieve the high performance of future nano-devices, such as nanosized electronic devices, optical devices, bio-devices and energy devices. Also, nanoimprint, e-beam, dip-pen, block copolymer and soft lithography techniques have been studied to realize high-performance nano-devices.
The dip-pen, e-beam and scanning probe microscope (SPM) lithography techniques capable of showing the highest resolution have an advantage capable of fabricating high-resolution patterns on the order of tens of nanometers, but suffer from a disadvantage in that they have significantly slow processing speeds, because they involve scanning with a tip. In addition, these techniques have to use expensive equipment that limit the actual use of these techniques in research and production.
Also, the nanoimprint and soft lithography techniques capable of fabricating nanopatterns in large area within a relatively short process time have an advantage in that a pattern having the size of a mask mold can be repeatedly transferred to a large-area substrate, but suffer from limitations in that it is impossible to fabricate a pattern having a size smaller than that of the mask mold and in that it is very expensive to fabricate a mask of less than 100 nm. Moreover, in these lithography techniques, because a pattern is fabricated using a stamping or etching process, only the two-dimensional shape of the mask mold is transferred as it is, and thus it is impossible to fabricate a three-dimensional pattern. In addition, when nanostructured patterns of other sizes or shapes are to be fabricated, other mask molds should be fabricated.
Accordingly, the present inventors have made many efforts to solve the above-mentioned problems occurring in the prior art and, as a result, have found that three-dimensional nanostructures of various shapes having high aspect ratio and uniformity can be fabricated by attaching a target material to the outer surface of patterned polymer structures using an ion bombardment phenomenon occurring during an ion etching process to form target material-polymer composite structures, and then removing the polymer from the target material-polymer composite structures, thereby completing the present invention.